1. Field of the Invention
This invention relates generally to the coupling between a tractor and a trailer in a tractor-trailer combination, and particularly to a safety stop arrangement for preventing excessive angular movement between a tractor and trailer and for permitting the trailer to separate from the tractor when the forces causing relative movement between a trailer and its associated tractor become excessive, as in extreme jackknifing situations and the like.
2. Description of the Prior Art
The conventional tractor-trailer combination has traditionally had difficulties with the tractor and trailer coming too close together, and even striking one another, when the rig is being parked or backed up, and when a jackknifing situation occurs. The latter is merely a generic term describing various conditions of uncontrolled movement the rig, such as striking another vehicle, skidding, and other mishaps. In both instances, the basic problem is that the angular disposition between the trailer and the tractor becomes essentially zero and the tractor strikes against the trailer, with potentially great damage resulting.
Various proposals have been made for preventing the tractor and trailer of a tractor-trailer combination from coming together in the manner described above. Examples of the known devices can be found in U.S. Pat. Nos. 2,146,145, issued Feb. 7, 1939, to J. D. Huffman, et al.; 2,723,865, issued Nov. 15, 1955, to A. L. Leoni; 2,772,894, issued Dec. 4, 1956, to W. K. Oats; and 2,773,701, issued Dec. 11, 1956, to W. T. Safko. While the aforementioned prior patents relate to mechanical limit stop arrangements or tractor-trailer combinations, U.S. Pat. Nos. 3,517,946, issued June 30, 1970, to R. D. Rumsey, et al. and 3,520,557, issued July 14, 1970, to G. W. Kamman, et al., disclose devices dampen the relative movement between the tractor and trailer in order to limit same.